Publications by authors named "Lisa Keller"

Aerobic and anaerobic organisms and their functions are spatially or temporally decoupled at scales ranging from individual cells to ecosystems and from minutes to hours. This is due to competition for energy substrates and/or biochemical incompatibility with oxygen (O). Here we report a chemolithotrophic Aquificales bacterium, Hydrogenobacter, isolated from a circumneutral hot spring in Yellowstone National Park (YNP) capable of simultaneous aerobic and anaerobic respiration when provided with hydrogen (H), elemental sulfur (S), and O.

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In educational assessment, cut scores are often defined through standard setting by a group of subject matter experts. This study aims to investigate the impact of several factors on classification accuracy using the receiver operating characteristic (ROC) analysis to provide statistical and theoretical evidence when the cut score needs to be refined. Factors examined in the study include the sample distribution relative to the cut score, prevalence of the positive event, and cost ratio.

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Molybdoenzymes are essential in global nitrogen, carbon, and sulfur cycling. To date, the only known bioavailable source of molybdenum (Mo) is molybdate. However, in the sulfidic and anoxic (euxinic) habitats that predominate in modern subsurface environments and that were pervasive prior to Earth's widespread oxygenation, Mo occurs as soluble tetrathiomolybdate ion and molybdenite mineral that is not known to be bioavailable.

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The geosphere and the microbial biosphere have co-evolved for ~3.8 Ga, with many lines of evidence suggesting a hydrothermal habitat for life's origin. However, the extent that contemporary thermophiles and their hydrothermal habitats reflect those that likely existed on early Earth remains unknown.

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Consolidated bioprocessing (CBP) of lignocellulosic biomass holds promise to realize economic production of second-generation biofuels/chemicals, and Clostridium thermocellum is a leading candidate for CBP due to it being one of the fastest degraders of crystalline cellulose and lignocellulosic biomass. However, CBP by C. thermocellum is approached with co-cultures, because C.

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Natural thermal geysers are hot springs that periodically erupt liquid water, steam, and gas. They are found in only a few locations worldwide, with nearly half located in Yellowstone National Park (YNP). Old Faithful geyser (OFG) is the most iconic in YNP and attracts millions of visitors annually.

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The influence of mineralogy on the assembly of microbial communities in glacial environments has been difficult to assess due to complications in isolating mineralogy from other variables. Here we assess the abundance and composition of microbial communities that colonized defined minerals incubated for 12 months in two meltwater streams (N and S) emanating from Kaldalónsjökull (Kal), a basalt-hosted glacier in Iceland. The two streams shared similar meltwater geochemistry as well as bedrock and proglacial sediment elemental compositions.

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Article Synopsis
  • The text discusses the cultivation of a unique archaeal species called Wolframiiraptor gerlachensis, which relies on tungsten for its growth, showcasing the importance of trace metals in life.
  • Research included genetic analysis revealing that W. gerlachensis possesses tungsten transport systems and enzymes for anaerobic sugar oxidation, indicating a specialized metabolism linked to tungsten.
  • Phylogenetic studies suggest that tungsten-dependent enzymes have deep evolutionary roots in the Wolframiiraptoraceae family, highlighting tungsten's potential role in early life forms and ecosystems.
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Little is known of how the confluence of subsurface and surface processes influences the assembly and habitability of hydrothermal ecosystems. To address this knowledge gap, the geochemical and microbial composition of a high-temperature, circumneutral hot spring in Yellowstone National Park was examined to identify the sources of solutes and their effect on the ecology of microbial inhabitants. Metagenomic analysis showed that populations comprising planktonic and sediment communities are archaeal dominated, are dependent on chemical energy (chemosynthetic), share little overlap in their taxonomic composition, and are differentiated by their inferred use of/tolerance to oxygen and mode of carbon metabolism.

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Background: Triple therapy (TT) consisting of furosemide, pimobendan, and an angiotensin-converting enzyme inhibitor (ACEI) frequently is recommended for the treatment of congestive heart failure (CHF) attributable to myxomatous mitral valve disease (MMVD). However, the effect of adding an ACEI to the combination of pimobendan and furosemide (dual therapy [DT]) so far has not been evaluated prospectively.

Hypothesis: Triple therapy will extend survival time compared to DT in dogs with CHF secondary to MMVD.

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The production of volatile industrial chemicals utilizing metabolically engineered extreme thermophiles offers the potential for processes with simultaneous fermentation and product separation. An excellent target chemical for such a process is acetone (T  = 56°C), ideally produced from lignocellulosic biomass. Caldicellulosiruptor bescii (T 78°C), an extremely thermophilic fermentative bacterium naturally capable of deconstructing and fermenting lignocellulose, was metabolically engineered to produce acetone.

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The establishment of protective humoral immunity is dependent on the ability of mature B cells to undergo antibody gene diversification while adjusting to the physiological stressors induced by activation with the antigen. Mature B cells diversify their antibody genes by class switch recombination (CSR) and somatic hypermutation (SHM), which are both dependent on efficient induction of activation-induced cytidine deaminase (AID). Here, we identified PDGFA-associated protein 1 (Pdap1) as an essential regulator of cellular homeostasis in mature B cells.

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The key difference in the modified Embden-Meyerhof glycolytic pathway in hyperthermophilic Archaea, such as Pyrococcus furiosus, occurs at the conversion from glyceraldehyde-3-phosphate (GAP) to 3-phosphoglycerate (3-PG) where the typical intermediate 1,3-bisphosphoglycerate (1,3-BPG) is not present. The absence of the ATP-yielding step catalyzed by phosphoglycerate kinase (PGK) alters energy yield, redox energetics, and kinetics of carbohydrate metabolism. Either of the two enzymes, ferredoxin-dependent glyceraldehyde-3-phosphate ferredoxin oxidoreductase (GAPOR) or NADP-dependent non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN), responsible for this "bypass" reaction, could be deleted individually without impacting viability, albeit with differences in native fermentation product profiles.

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Microbial mat communities are associated with extensive (∼700 km) and morphologically variable carbonate structures, termed microbialites, in the hypersaline Great Salt Lake (GSL), Utah. However, whether the composition of GSL mat communities covaries with microbialite morphology and lake environment is unknown. Moreover, the potential adaptations that allow the establishment of these extensive mat communities at high salinity (14% to 17% total salts) are poorly understood.

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Background: Today, nearly two thirds of inpatients in trauma surgery hospitals are over 70 years old and at significant risk for comorbidities. These patients frequently suffer delirium. Delirium occurs in 15 - 30% of these trauma patients and increases the risk of mortality in up to 15 - 25% of cases.

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Species in the archaeal order Sulfolobales thrive in hot acid and exhibit remarkable metabolic diversity. Some species are chemolithoautotrophic, obtaining energy through the oxidation of inorganic substrates, sulphur in particular, and acquiring carbon through the 3-hydroxypropionate/4-hydroxybutyrate (3-HP/4-HB) CO -fixation cycle. The current model for sulphur oxidation in the Sulfolobales is based on the biochemical analysis of specific proteins from Acidianus ambivalens, including sulphur oxygenase reductase (SOR) that disproportionates S° into H S and sulphite (SO ).

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A preference-based quality-of-life index for non-small cell lung cancer was developed with a subset of Functional Assessment of Cancer Therapy (FACT)-General (G) and FACT-Lung (L) items, based on clinician input and the literature. A total of 236 non-small cell lung carcinoma patients contributed their preferences, randomly allocated among three survey groups to decrease burden. The FACT-L Utility Index (FACT-LUI) was constructed with two methods: 1) multiattribute utility theory (MAUT), where a visual analog scale (VAS)-based index was transformed to standard gamble (SG); and 2) an unweighted index, where items were summed, normalized to a 0 to 1.

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Class switch recombination (CSR) is a DNA recombination reaction that diversifies the effector component of antibody responses. CSR is initiated by activation-induced cytidine deaminase (AID), which targets transcriptionally active immunoglobulin heavy chain (Igh) switch donor and acceptor DNA. The 3' Igh super-enhancer, 3' regulatory region (3'RR), is essential for acceptor region transcription, but how this function is regulated is unknown.

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Purpose: Physical activity can impact the immune system in different ways, e.g. by alteration of the humoral and cellular immune response.

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Background: Chronic and refractory cancer pain are significant issues and can increase patient suffering and compromise quality of life. A variety of evidence-based pharmacologic strategies can be used routinely to control cancer pain. 
.

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Purpose: The Radiology Process Model (RPM) was previously described in terms of its conceptual basis and proposed survey items. The current study describes the first pilot application of the RPM in the field and the results of initial psychometric analysis.

Methods: We used an Institutional Review Board-approved pilot RPM survey in 100 patients having outpatient interventional radiology procedures.

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Clostridium difficile is the most frequent cause of health care-associated diarrhea and is a significant cause of morbidity and mortality. It is also associated with a considerable financial burden. A concerted multidisciplinary approach is required for prevention.

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Hospitalized sub-acute medicine patients face challenges to their functional and cognitive abilities as they await transfer to long-term care facilities or return home. The Continuous Quality Improvement (CQI) Council, representing a multidisciplinary team of healthcare professionals working in the Sub-Acute Medicine Unit (SAMU), implemented a twice-weekly lunch program called the Lunch Bunch in order to combat depression and delirium in our elderly and cognitively impaired patients. The Lunch Bunch initiative includes chaplains, nurses and physiotherapists who have provided a framework through which essential socialization and exercise for this vulnerable population is facilitated.

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Dilated cardiomyopathy (DCM) is a heterogeneous group of heart diseases with a strong genetic background. Currently, many human DCM cases exist where no causative mutation can be identified. DCM also occurs with high prevalence in several large dog breeds.

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